Prepolymer composition, polyurethane resin, elastic molded article, and method for producing prepolymer composition

Abstract

This prepolymer composition contains an isocyanate group-terminated prepolymer. The isocyanate group-terminated prepolymer contains a product of a reaction between a polyol component and a polyisocyanate component including 1,4-bis(isocyanatomethyl)cyclohexane. The polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer is 1.85 or less. The isocyanate group concentration in the prepolymer composition is 14.0 mass% or less.

Description

[Technical Field]

[0001] The present invention relates to a prepolymer composition, a polyurethane resin, an elastic molded article, and a method for producing the prepolymer composition. [Background technology]

[0002] The polyurethane resin has, for example, a soft segment formed by the reaction of a polyisocyanate and a macropolyol, and a hard segment formed by the reaction of a polyisocyanate and a chain extender.

[0003] More specifically, a polyurethane resin obtained by the following method is known. First, 1,118 parts by mass of 1,4-bis(isocyanatomethyl)cyclohexane is reacted with 2,881 parts by mass of polytetramethylene ether glycol having a number-average molecular weight of 1,000 to obtain an isocyanate-terminated prepolymer. Next, 150 parts by mass of the isocyanate-terminated prepolymer and 7.62 to 8.71 parts by mass of 1,4-butylene glycol are preheated to 80°C and mixed. The equivalent ratio (NCO / active hydrogen groups) is 1.12 to 1.28. Furthermore, 0.0008 parts by mass of dibutyltin dilaurate is added to the mixture, which is then poured into a mold and cured at 110°C for 24 hours to obtain a polyurethane elastomer (see, for example, Patent Document 1 (Synthesis Example 1 and Examples 1 to 5)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-231585 Summary of the Invention [Problem to be solved by the invention]

[0005] The polyurethane elastomers described above have excellent mechanical properties. However, they may have high heat buildup. Furthermore, polyurethane elastomers are required to have further improved mechanical properties.

[0006] The present invention includes a prepolymer composition for producing a polyurethane resin having both excellent mechanical properties (high hardness) and low heat buildup, a polyurethane resin and an elastic molded article obtained from the prepolymer composition, and a method for producing the prepolymer composition. [Means for solving the problem]

[0007] The present invention [1] is a prepolymer composition containing an isocyanate group-terminated prepolymer, wherein the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component, the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer being 1.85 or less, and the isocyanate group concentration of the prepolymer composition being 14.0 mass% or less.

[0008] The present invention [2] comprises a polyurethane resin comprising a reaction product of a prepolymer composition containing an isocyanate group-terminated prepolymer and a chain extension component, wherein the isocyanate group-terminated prepolymer comprises a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component, wherein the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer is 1.85 or less, and the isocyanate group concentration of the prepolymer composition is 14.0 mass% or less.

[0009] The present invention [3] includes an elastic molded article containing the polyurethane resin described in [2] above.

[0010] The present invention [4] is a method for producing a prepolymer composition containing an isocyanate-terminated prepolymer, comprising: a first step of reacting a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane with a polyol component to prepare a reaction product liquid containing an isocyanate-terminated prepolymer; and a second step of distilling the reaction product liquid, wherein in the first step, the equivalent ratio (NCO / OH) of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the polyol component is 7.0 or more, the polydispersity (Mw / Mn) of the isocyanate-terminated prepolymer is 1.85 or less, and the isocyanate group concentration of the prepolymer composition is 14.0 mass% or less.

[0011] The present invention [5] includes the method for producing a prepolymer composition described in the above [4], which includes a third step of adding an isocyanate monomer to the purified liquid obtained by the distillation after the second step, and the isocyanate monomer contains 1,4-bis(isocyanatomethyl)cyclohexane. [Effects of the Invention]

[0012] In the present invention, the isocyanate group concentration of the prepolymer composition is less than a predetermined value, and the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer contained in the prepolymer composition is less than a predetermined value.

[0013] Therefore, the prepolymer composition of the present invention can provide a polyurethane resin that has both excellent mechanical properties (high hardness) and low heat buildup.

[0014] The polyurethane resin and elastic molded article of the present invention have both excellent mechanical properties (high hardness) and low heat buildup.

[0015] According to the method for producing a prepolymer composition of the present invention, the above prepolymer composition can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0016] The polyurethane resin contains a reaction product of a prepolymer composition (first liquid) and a chain-extending component (second liquid). The prepolymer composition (first liquid) and the chain-extending component (second liquid) are prepared, for example, as a resin kit, and are mixed together to undergo a urethane reaction.

[0017] The polyurethane resin is preferably a reaction product of a prepolymer composition (first liquid) and a chain-extending component (second liquid). That is, the polyurethane resin is preferably a cured urethane product obtained by reacting and curing the prepolymer composition and the chain-extending component.

[0018] The prepolymer composition (first liquid) contains an isocyanate group-terminated prepolymer as an essential component.

[0019] The isocyanate-terminated prepolymer comprises a reaction product of a polyisocyanate component and a polyol component. Preferably, the isocyanate-terminated prepolymer comprises a reaction product of a polyisocyanate component and a polyol component.

[0020] The polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane as an essential component. 1,4-bis(isocyanatomethyl)cyclohexane has two stereoisomers: cis-1,4-bis(isocyanatomethyl)cyclohexane and trans-1,4-bis(isocyanatomethyl)cyclohexane. Hereinafter, cis-1,4-bis(isocyanatomethyl)cyclohexane may be referred to as the cis-1,4 isomer. Trans-1,4-bis(isocyanatomethyl)cyclohexane may be referred to as the trans-1,4 isomer. The total amount of the trans-1,4 isomer and the cis-1,4 isomer is 100 mol%.

[0021] In 1,4-bis(isocyanatomethyl)cyclohexane, the content of trans 1,4 isomer is, for example, 60 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 85 mol% or more. In addition, in 1,4-bis(isocyanatomethyl)cyclohexane, the content of trans 1,4 isomer is, for example, 100 mol% or less, preferably 99.8 mol% or less, more preferably 99 mol% or less, even more preferably 96 mol% or less, and even more preferably 90 mol% or less.

[0022] In 1,4-bis(isocyanatomethyl)cyclohexane, the content of cis-1,4 isomer is, for example, 0 mol% or more, preferably 0.2 mol% or more, more preferably 1 mol% or more, even more preferably 4 mol% or more, and still more preferably 10 mol% or more. In 1,4-bis(isocyanatomethyl)cyclohexane, the content of cis-1,4 isomer is, for example, 40 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less, and still more preferably 15 mol% or less.

[0023] When the content of the trans 1,4 isomer and the content of the cis 1,4 isomer are within the above ranges, a polyurethane resin having excellent mechanical strength can be obtained.

[0024] Furthermore, 1,4-bis(isocyanatomethyl)cyclohexane may be modified to the extent that the excellent effects of the present invention are not impaired. Examples of modified products include uretdione-modified products, isocyanurate-modified products, iminooxadiazinedione-modified products, biuret-modified products, allophanate-modified products, polyol adducts, oxadiazinetrione-modified products, and carbodiimide-modified products.

[0025] The polyisocyanate component may optionally contain isocyanates other than 1,4-bis(isocyanatomethyl)cyclohexane (hereinafter referred to as "other polyisocyanates"), provided that the excellent effects of the present invention are not impaired. Examples of other polyisocyanates include diisocyanates.

[0026] Specific examples of other polyisocyanates include aliphatic polyisocyanates, alicyclic polyisocyanates (excluding 1,4-bis(isocyanatomethyl)cyclohexane), aromatic polyisocyanates, and araliphatic polyisocyanates. Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 1,2-propane diisocyanate, 1,2-butane diisocyanate, 2,3-butane diisocyanate, 1,3-butane diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methylcaproate. Examples of alicyclic polyisocyanates include 1,3-bis(isocyanatomethyl)cyclohexane (1,3-H6XDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and methylenebis(cyclohexyl isocyanate) (H 12 Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), paraphenylene diisocyanate, and naphthalene diisocyanate (NDI). Examples of aromatic aliphatic polyisocyanates include xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI). Furthermore, other polyisocyanates may be modified as described above, provided that the excellent effects of the present invention are not impaired. These may be used alone or in combination of two or more.

[0027] The content of the other polyisocyanates is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass, relative to the total amount of the polyisocyanate components. The content of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the total amount of the polyisocyanate components. That is, the polyisocyanate components are particularly preferably composed of 1,4-bis(isocyanatomethyl)cyclohexane.

[0028] The polyol component includes, for example, a macropolyol. A macropolyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively high molecular weight. A relatively high molecular weight indicates a number average molecular weight of more than 400.

[0029] Examples of the macropolyol include polyether polyol, polyester polyol, polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, acrylic polyol, and vinyl monomer-modified polyol. Preferred examples of the macropolyol include polyether polyol, polyester polyol, and polycarbonate polyol.

[0030] Examples of polyether polyols include polyoxyalkylene polyols, such as polyoxyalkylene (C2-3) polyols and polytetramethylene ether polyols.

[0031] Examples of polyester polyols include condensation polyester polyols and ring-opening polyester polyols. Examples of condensation polyester polyols include adipate-based polyester polyols (e.g., polybutylene adipate) and phthalate-based polyester polyols. Examples of ring-opening polyester polyols include lactone-based polyester polyols, more specifically, polycaprolactone polyols.

[0032] An example of the polycarbonate polyol is a ring-opening polymer of ethylene carbonate using a low-molecular-weight polyol as an initiator, as described below.

[0033] These macropolyols can be used alone or in combination of two or more. From the viewpoints of low heat buildup and mechanical properties, the macropolyol is preferably a polyether polyol, more preferably a polytetramethylene ether polyol.

[0034] The number average molecular weight of the macropolyol exceeds 400, preferably 500 or more, more preferably 650 or more, and even more preferably 1000 or more. The number average molecular weight of the macropolyol is, for example, 5000 or less, preferably 3000 or less, more preferably 2000 or less, and even more preferably 1500 or less. The average number of functional groups (average number of hydroxyl groups) of the macropolyol is, for example, 2 or more. The average number of functional groups (average number of hydroxyl groups) of the macropolyol is, for example, 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2.5 or less.

[0035] The hydroxyl value of the macropolyol is, for example, 50 mg KOH / g or more, preferably 100 mg KOH / g or more. The hydroxyl value of the macropolyol is, for example, 400 mg KOH / g or less, preferably 300 mg KOH / g or less, more preferably 180 mg KOH / g or less, and even more preferably 150 mg KOH / g or less. The hydroxyl value can be measured by a known hydroxyl value measurement method. Examples of hydroxyl value measurement methods include the acetylation method and the phthalation method. The hydroxyl value can also be calculated from the raw material ratio of the macropolyol.

[0036] The polyol component may include a low molecular weight polyol.

[0037] A low-molecular-weight polyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively low molecular weight. A relatively low molecular weight means that the number-average molecular weight is 400 or less. That is, the molecular weight of the low-molecular-weight polyol is, for example, 400 or less, preferably 300 or less. The molecular weight of the low-molecular-weight polyol is usually 40 or more.

[0038] Examples of low-molecular-weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. Examples of low-molecular-weight polyols include polymers obtained by addition polymerization of alkylene (C2-C3) oxide with dihydric to tetrahydric alcohols to give a number-average molecular weight of 400 or less. These may be used alone or in combination.

[0039] The content of the low molecular weight polyol is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, and particularly preferably 0% by mass, based on the total amount of the polyol components. The content of the macro polyol is, for example, 90% by mass or more, preferably 95% by mass or more, more preferably 99% by mass or more, and particularly preferably 100% by mass, based on the total amount of the polyol components. That is, the polyol component is particularly preferably composed of a macro polyol.

[0040] The method for producing the isocyanate group-terminated prepolymer will be described later.

[0041] The content of the isocyanate group-terminated prepolymer is appropriately set so that the isocyanate group concentration in the prepolymer composition falls within the range described below.

[0042] More specifically, the isocyanate-terminated prepolymer accounts for, for example, 75% by mass or more, preferably 80% by mass or more, and more preferably 85% by mass or more, relative to the total amount of the prepolymer composition, and the isocyanate-terminated prepolymer accounts for, for example, 100% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, relative to the total amount of the prepolymer composition.

[0043] The isocyanate group concentration of the isocyanate group-terminated prepolymer is, for example, 3.0% by mass or more, preferably 5.0% by mass or more. The isocyanate group concentration of the isocyanate group-terminated prepolymer is, for example, 20.0% by mass or less, preferably 15.0% by mass or less, and more preferably 10.0% by mass or less. The isocyanate group concentration can be determined by known measurement methods. Examples of measurement methods include titration with di-n-butylamine and FT-IR analysis (the same applies below).

[0044] The weight average molecular weight (Mw) of the isocyanate group-terminated prepolymer is, for example, 1500 or more, preferably 2000 or more, more preferably 2500 or more, and even more preferably 3000 or more. The weight average molecular weight of the isocyanate group-terminated prepolymer is, for example, 5000 or less, preferably 4000 or less, and more preferably 3500 or less. The weight average molecular weight can be measured by a known gel permeation chromatogram (GPC) (the same applies hereinafter). Details of the GPC measurement conditions will be described later in the examples.

[0045] The number-average molecular weight (Mn) of the isocyanate-terminated prepolymer is usually smaller than the weight-average molecular weight (Mw) of the isocyanate-terminated prepolymer. More specifically, the number-average molecular weight (Mn) of the isocyanate-terminated prepolymer is, for example, 500 or more, preferably 1000 or more, more preferably 1500 or more, and even more preferably 2000 or more. The number-average molecular weight of the isocyanate-terminated prepolymer is, for example, 3000 or less, preferably 2500 or less, and more preferably 2000 or less. The number-average molecular weight can be measured by known gel permeation chromatography (GPC) (the same applies hereinafter). Details of the GPC measurement conditions will be described later in the Examples.

[0046] The weight average molecular weight and number average molecular weight of the isocyanate group-terminated prepolymer are calculated, for example, by subjecting a purified liquid of the isocyanate group-terminated prepolymer (described below) to GPC measurement.

[0047] The weight-average molecular weight and number-average molecular weight of the isocyanate-terminated prepolymer can also be measured as the weight-average molecular weight and number-average molecular weight of the portion excluding the isocyanate monomer from the prepolymer composition described below. That is, the peak attributable to the isocyanate-terminated prepolymer and the peak attributable to the isocyanate monomer can be separated in a GPC chart, and the weight-average molecular weight and number-average molecular weight of the isocyanate-terminated prepolymer can be calculated based on the peak attributable to the isocyanate-terminated prepolymer.

[0048] The dispersity (Mw / Mn) of the isocyanate-terminated prepolymer is 1.85 or less, preferably 1.80 or less, more preferably 1.75 or less, even more preferably 1.70 or less, and particularly preferably 1.68 or less. The dispersity (Mw / Mn) of the isocyanate-terminated prepolymer is, for example, 1.0 or more, preferably 1.2 or more, and more preferably 1.4 or more.

[0049] If the dispersity of the isocyanate group-terminated prepolymer is below the above upper limit, a polyurethane resin having excellent low heat generation properties can be obtained.

[0050] On the other hand, if the dispersity of the isocyanate group-terminated prepolymer is below the upper limit, the mechanical properties of the polyurethane resin may be insufficient depending on the isocyanate group concentration of the isocyanate group-terminated prepolymer.

[0051] In such cases, in order to improve the mechanical properties of the polyurethane resin, an isocyanate monomer can be added to the isocyanate group-terminated prepolymer to adjust the isocyanate group concentration in the prepolymer composition.

[0052] In other words, the prepolymer composition can contain an isocyanate monomer as an optional component in addition to the isocyanate group-terminated prepolymer. Preferably, the prepolymer composition contains an isocyanate group-terminated prepolymer and an isocyanate monomer.

[0053] Examples of isocyanate monomers include the above-mentioned 1,4-bis(isocyanatomethyl)cyclohexane and the above-mentioned other polyisocyanates (isocyanates other than 1,4-bis(isocyanatomethyl)cyclohexane). These can be used alone or in combination of two or more.

[0054] The isocyanate monomer is preferably 1,4-bis(isocyanatomethyl)cyclohexane. That is, the isocyanate monomer preferably contains 1,4-bis(isocyanatomethyl)cyclohexane, and more preferably consists of 1,4-bis(isocyanatomethyl)cyclohexane. In the 1,4-bis(isocyanatomethyl)cyclohexane, the content ratio of the trans-1,4 isomer and the cis-1,4 isomer is preferably within the above-mentioned range.

[0055] The isocyanate monomer is mixed with the isocyanate group-terminated prepolymer in the third step described below, for example, so that the isocyanate monomer is contained in the prepolymer composition.

[0056] The content of the isocyanate monomer is appropriately set so that the isocyanate group concentration in the prepolymer composition falls within the range described below.

[0057] More specifically, the content of the isocyanate monomer relative to the total amount of the prepolymer composition is, for example, 0% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, and for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total amount of the prepolymer composition.

[0058] The method for producing the prepolymer composition will be described later.

[0059] From the viewpoint of mechanical properties, the isocyanate group concentration of the prepolymer composition is, for example, 5.0 mass% or more, preferably 7.0 mass% or more, more preferably 9.0 mass% or more, even more preferably 10.0 mass% or more, and particularly preferably 12.0 mass% or more.

[0060] From the viewpoint of low heat generation, the isocyanate group concentration of the prepolymer composition is 14.0 mass % or less, preferably 13.5 mass % or less, more preferably 13.0 mass % or less, and even more preferably 12.5 mass % or less.

[0061] The prepolymer composition may optionally contain additives. Examples of additives include urethane catalysts (e.g., organometallic catalysts), catalyst activity modifiers (e.g., acetylacetone), antioxidants, heat stabilizers, light stabilizers, UV absorbers, antiblocking agents, mold release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0062] The chain extension component (second liquid) contains, for example, a chain extender (chain extension compound).

[0063] The chain extender is a curing agent for the prepolymer composition. Examples of the chain extender include low molecular weight polyols and low molecular weight polyamines. A preferred chain extender is a low molecular weight polyol. By using a low molecular weight polyol, a polyurethane resin having excellent mechanical strength can be obtained.

[0064] Examples of low-molecular-weight polyols include the above-mentioned low-molecular-weight polyols. More specifically, examples of low-molecular-weight polyols include the above-mentioned dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. These can be used alone or in combination of two or more.

[0065] The low-molecular-weight polyol is preferably a dihydric alcohol or a trihydric alcohol, more preferably a dihydric alcohol, and even more preferably 1,4-butanediol. That is, the low-molecular-weight polyol preferably contains 1,4-butanediol, and more preferably consists of 1,4-butanediol. This allows for the production of a polyurethane resin with excellent mechanical strength.

[0066] The chain-extending component may optionally contain additives. Examples of additives include urethane catalysts (e.g., organometallic catalysts), catalyst activity modifiers (e.g., acetylacetone), antioxidants, heat stabilizers, light stabilizers, UV absorbers, antiblocking agents, mold release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0067] The method for producing the prepolymer composition and the method for producing the polyurethane resin will be described in detail below.

[0068] In this method, first, an isocyanate-terminated prepolymer is synthesized (Step 1). Next, the isocyanate-terminated prepolymer is purified (Step 2). Next, an isocyanate monomer is blended (Step 3). After that, a polyurethane resin is synthesized (Step 4).

[0069] More specifically, in this method, first, the polyisocyanate component and the polyol component are reacted in a predetermined ratio to prepare a reaction product liquid containing an isocyanate group-terminated prepolymer (first step).

[0070] The blending ratio of the polyisocyanate component and the polyol component is adjusted so that the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer falls within the above range.

[0071] More specifically, in the first step, the equivalent ratio R(NCO / OH) of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the polyol component is 7.0 or more, preferably 7.5 or more, more preferably 8.0 or more, and even more preferably 8.5 or more. Also, the equivalent ratio R(NCO / OH) of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the polyol component is, for example, 20 or less, preferably 15 or less. When the blending ratio of the polyisocyanate component and the polyol component is within the above range, the degree of dispersion of the isocyanate group-terminated prepolymer can be made relatively low.

[0072] In the first step, examples of the reaction method include bulk polymerization and solution polymerization. In bulk polymerization, for example, the polyisocyanate component and the polyol component are reacted under a nitrogen gas flow. The reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 250°C or lower, preferably 200°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 15 hours or lower. In solution polymerization, the polyisocyanate component and the polyol component are reacted in the presence of a known organic solvent. The reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 120°C or lower, preferably 100°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 15 hours or lower.

[0073] This produces a reaction liquid containing an isocyanate-terminated prepolymer. The isocyanate group concentration of the reaction liquid is, for example, 10.0% by mass or more, preferably 20.0% by mass or more. The isocyanate group concentration of the reaction liquid is, for example, 50.0% by mass or less, preferably 40.0% by mass or less.

[0074] Next, in this method, the reaction product liquid is purified (second step), thereby obtaining an isocyanate group-terminated prepolymer as a purified liquid.

[0075] Examples of the purification method include distillation and extraction. Preferably, the purification method is distillation. In other words, in the second step, the reaction product liquid is preferably purified by distillation to obtain a purified liquid.

[0076] The distillation method is not particularly limited, but includes, for example, a batch distillation method and a continuous distillation method, and preferably includes a continuous distillation method. An example of the continuous distillation method is a thin film distillation method (Smith thin film distillation method). A preferred distillation method is a thin film distillation method (Smith thin film distillation method).

[0077] In the thin film distillation method, the distillation temperature is, for example, 120° C. or higher, preferably 150° C. or higher, and for example, 250° C. or lower, preferably 200° C. or lower. The distillation pressure (absolute pressure) is, for example, 1 Pa or more, preferably 10 Pa or more, more preferably 50 Pa or more. The distillation pressure (absolute pressure) is, for example, 300 Pa or less, preferably 200 Pa or less, more preferably 100 Pa or less.

[0078] The reaction product liquid feed rate is, for example, 0.1 g / min or more, preferably 1.0 g / min or more, more preferably 2.0 g / min or more, and for example, 100 g / min or less, preferably 50 g / min or less, more preferably 10 g / min or less.

[0079] This removes unreacted polyisocyanate components from the reaction product liquid of the first step. As a result, an isocyanate-terminated prepolymer is obtained as a purified liquid. The weight-average molecular weight, number-average molecular weight, and polydispersity of the isocyanate-terminated prepolymer are within the above-mentioned ranges.

[0080] The isocyanate-terminated prepolymer may contain unreacted polyisocyanate components as unavoidable impurities. The proportion of the unreacted polyisocyanate components relative to the total amount of the isocyanate-terminated prepolymer and the unreacted polyisocyanate components is, for example, 0.1% by mass or less. In other words, the purity of the isocyanate-terminated prepolymer is, for example, 99.9% by mass or more.

[0081] Next, in this method, the above-mentioned isocyanate monomer is added to the above-mentioned isocyanate group-terminated prepolymer (purified liquid) to prepare a prepolymer composition (third step).

[0082] In the third step, the mixing ratio of the isocyanate group-terminated prepolymer and the isocyanate monomer is adjusted so that the isocyanate group concentration in the prepolymer composition falls within the above range.

[0083] More specifically, the isocyanate group-terminated prepolymer accounts for, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the isocyanate group-terminated prepolymer and the isocyanate monomer. The isocyanate group-terminated prepolymer accounts for, for example, 98% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less. The isocyanate monomer accounts for, for example, 2% by mass or more, preferably 5% by mass or more, and more preferably 10% by mass or more. The isocyanate monomer accounts for, for example, 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0084] This results in the preparation of a prepolymer composition containing the isocyanate group-terminated prepolymer and the isocyanate monomer, the isocyanate group concentration of which is within the above-mentioned range.

[0085] The method then involves reacting the prepolymer composition with a chain extender (fourth step).

[0086] More specifically, the blending ratio of the prepolymer composition and the chain extender is such that the equivalent ratio R(NCO / OH) of the isocyanate groups in the prepolymer composition to the hydroxyl groups in the chain extender (chain extender) is, for example, 0.90 or more, preferably 1.00 or more, and the equivalent ratio R(NCO / OH) of the isocyanate groups in the prepolymer composition to the hydroxyl groups in the chain extender (chain extender) is, for example, 1.33 or less, preferably 1.25 or less.

[0087] In the fourth step, examples of the reaction method include the bulk polymerization and solution polymerization. In bulk polymerization, the reaction temperature is, for example, 50°C or higher, preferably 100°C or higher. The reaction temperature is, for example, 250°C or lower, preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 150°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 24 hours or lower, preferably 20 hours or lower, and more preferably 18 hours or lower. In solution polymerization, the reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 120°C or lower, preferably 150°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 24 hours or lower. If necessary, a known urethanization catalyst can be added. The urethanization catalyst is added in an amount of, for example, 5 ppm or higher, preferably 10 ppm or higher, more preferably 30 ppm or higher, and even more preferably 50 ppm or higher, relative to the total amount of the prepolymer composition, the chain extender, and the urethanization catalyst. The urethanization catalyst is added in an amount of, for example, 1000 ppm or lower, preferably 500 ppm or lower, more preferably 300 ppm or lower, and even more preferably 200 ppm or lower, relative to the total amount of the prepolymer composition, the chain extender, and the urethanization catalyst.

[0088] This results in a polyurethane resin containing a reaction product of the prepolymer composition and the chain extender. Preferably, the mixture of the prepolymer composition and the chain extender is degassed as needed, cured in a preheated mold, and then demolded. This results in a polyurethane resin molded into a desired shape.

[0089] In the above-described method, a reaction product liquid containing an isocyanate-terminated prepolymer is prepared (Step 1), the isocyanate-terminated prepolymer is purified by distillation (Step 2), and then the isocyanate-terminated prepolymer is mixed with an isocyanate monomer (Step 3). However, Step 2 and / or Step 3 can be omitted as necessary.

[0090] That is, after preparing a reaction product liquid containing an isocyanate group-terminated prepolymer (first step), the isocyanate group-terminated prepolymer and an isocyanate monomer are mixed together (third step) without being purified as described above, thereby obtaining a prepolymer composition.

[0091] Furthermore, for example, after preparing a reaction product liquid containing an isocyanate group-terminated prepolymer (first step), the reaction product liquid is purified as described above (second step), and a prepolymer composition can be obtained as this purified liquid.

[0092] A polyurethane resin can also be obtained by subjecting such a prepolymer composition to the above-mentioned fourth step.

[0093] The polyurethane resin may be heat-treated as necessary. The heat treatment temperature is, for example, 50°C or higher, preferably 80°C or higher. The heat treatment temperature is, for example, 200°C or lower, preferably 150°C or lower. The heat treatment time is, for example, 30 minutes or longer, preferably 1 hour or longer. The heat treatment time is, for example, 30 hours or shorter, preferably 20 hours or shorter.

[0094] The polyurethane resin may be aged. The aging temperature is, for example, 10°C or higher, preferably 20°C or higher. The aging temperature is, for example, 50°C or lower, preferably 40°C or lower. The aging time is, for example, 1 hour or longer, preferably 10 hours or longer. The aging time is, for example, 50 days or shorter, preferably 30 days or shorter.

[0095] The polyurethane resin may contain known additives as needed. That is, the polyurethane resin may be a polyurethane resin composition. Examples of additives include urethanization catalysts, catalyst activity regulators, antioxidants, heat stabilizers, light stabilizers, UV absorbers, antiblocking agents, mold release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0096] The polyurethane resin has both excellent mechanical properties (high hardness) and low heat buildup.

[0097] That is, in the polyurethane resin, the isocyanate group concentration of the prepolymer composition is less than a predetermined value, and the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer contained in the prepolymer composition is less than a predetermined value.

[0098] Therefore, the prepolymer composition can provide a polyurethane resin that has both excellent mechanical properties (high hardness) and low heat buildup.

[0099] Moreover, the polyurethane resin has excellent mechanical properties (high hardness) and low heat generation.

[0100] As a result, the polyurethane resin and prepolymer composition are suitable for use in a variety of industrial fields that require high mechanical properties (high hardness) and low heat buildup, such as elastic molded products, paints, coating agents, and adhesives. Preferably, an elastic molded article is used.

[0101] Examples of the elastic molded article include polyurethane elastomers. Examples of polyurethane elastomers include TPU (thermoplastic polyurethane resin) and TSU (thermosetting polyurethane resin). Examples of the elastic molded article preferably include TSU (thermosetting polyurethane resin).

[0102] Elastic molded articles can be obtained by molding polyurethane resins using known molding methods, such as cast molding, thermocompression molding, injection molding, extrusion molding, and spinning. The molded shapes can be, for example, plates, fibers, strands, films, sheets, pipes, bottles, hollow bodies, boxes, and buttons.

[0103] The elastic molded article is preferably obtained by cast molding. Therefore, the elastic molded article is preferably a cast polyurethane elastomer. A cast polyurethane elastomer is a molded article (cast molded article) obtained by cast molding, and is an article that independently has a predetermined shape depending on the purpose and use, and is distinguished from a coating agent that is applied to a substrate.

[0104] Such elastic molded articles contain the polyurethane resin described above, and therefore have excellent mechanical strength and are able to suppress the inclusion of air bubbles, making them suitable for a variety of uses. Applications of elastic molded products include, for example, transparent hard plastics, waterproofing materials, potting agents, inks, binders, films, sheets, bands, belts, shoe press belts, tubes, blades, speakers, sensors, outsoles, yarns, fibers, nonwoven fabrics, cosmetics, shoe supplies, heat insulation materials, sealing materials, tapes, encapsulants, solar power generation components, robot components, android components, wearable components, clothing supplies, sanitary products, cosmetics, furniture supplies, food packaging components, sporting goods, leisure goods, medical supplies, nursing care products, housing components, acoustic components, lighting components, vibration-damping components, soundproofing components, daily necessities, miscellaneous goods, cushions, bedding, stress absorbing materials, stress relaxation materials, automotive interior materials, automotive exterior materials, railway components, aircraft components, optical components, office automation equipment components, miscellaneous surface protection materials, semiconductor encapsulants, self-repairing materials, health appliances, eyeglass lenses, toys, packing, cable sheaths, wire harnesses, telecommunications cables, automotive wiring, computer wiring, industrial products, shock absorbing materials, semiconductor supplies, polishing pads, and bridge bearings. [Example]

[0105] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited thereto. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, and parameters used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0106] 1.Raw materials <Polyisocyanate component, isocyanate monomer> Production Example 1 (1,4-H6XDI, trans isomer 93 mol %) 13Using 1,4-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Inc.) with a trans / cis ratio of 93 / 7 as determined by C-NMR, a two-stage cold-hot phosgenation method was carried out under pressure.

[0107] Specifically, 2,500 parts by mass of ortho-dichlorobenzene was charged into a jacketed pressure reactor equipped with an electromagnetic induction stirrer, an automatic pressure control valve, a thermometer, a nitrogen inlet line, a phosgene inlet line, a condenser, and a raw material feed pump. Next, 1,425 parts by mass of phosgene was added via the phosgene inlet line, and stirring was initiated. Cold water was passed through the reactor jacket to maintain the internal temperature at approximately 10°C. A solution of 400 parts by mass of 1,4-bis(aminomethyl)cyclohexane in 2,500 parts by mass of ortho-dichlorobenzene was fed into the reactor via a feed pump over 60 minutes, and cold phosgenation was carried out at 30°C or below under atmospheric pressure. After the feed was completed, the flask contained a pale brownish-white slurry.

[0108] The liquid in the reactor was then heated to 140°C over 60 minutes, pressurized to 0.25 MPa, and then thermally phosgenated for 2 hours at a pressure of 0.25 MPa and a reaction temperature of 140°C. During the thermal phosgenation, 480 parts by mass of phosgene was added. During the thermal phosgenation, the liquid in the flask became a clear, pale brown solution. After completion of the thermal phosgenation, nitrogen gas was passed through at 100 L / h at 100 to 140°C for degassing. The solvent, orthodichlorobenzene, was then distilled off under reduced pressure. The resulting mixture was then rectified under reflux at 138 to 143°C and 0.7 to 1 KPa using a rectification apparatus equipped with a distillation column packed with four packing elements (manufactured by Sumitomo Heavy Industries, Ltd., product name: Sumitomo / Sulzer Labopacking EX Type), a distillation column (manufactured by Shibata Scientific Co., Ltd., product name: Distillation Head K Type) equipped with a reflux ratio control timer, and a condenser. 382 parts by mass were obtained. The purity of the obtained 1,4-H6XDI was 99.9% by gas chromatography, and the color by APHA was 5. 13 The trans / cis ratio measured by C-NMR was 93 / 7. The hydrolyzable chlorine (HC) content was 19 ppm.

[0109] Production Example 2 (1,4-H6XDI, trans isomer 41 mol %) 13 Using 1,4-bis(aminomethyl)cyclohexane (manufactured by Tokyo Chemical Industry Co., Ltd.) having a trans / cis ratio of 41 / 59 as determined by C-NMR as a raw material, 388 parts by mass of 1,4-bis(isocyanatomethyl)cyclohexane having a trans / cis ratio of 41 / 59 was obtained in the same manner as in Production Example 1. The purity of the obtained 1,4-H6XDI was 99.9% as determined by gas chromatography, and the color was 5 as determined by APHA. 13 The trans / cis ratio measured by C-NMR was 41 / 59. HC was 22 ppm.

[0110] Production Example 3 (1,4-H6XDI, trans isomer 86 mol%) 865 parts by mass of 1,4-H6XDI (trans isomer 93 mol%) from Production Example 1 and 135 parts by mass of 1,4-H6XDI (trans isomer 41 mol%) from Production Example 2 were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, and stirred for 1 hour at room temperature under a nitrogen atmosphere. The purity of the resulting 1,4-H6XDI measured by gas chromatography was 99.9%, the color was 5 by APHA measurement, and the like. 13 The trans / cis ratio measured by C-NMR was 86 / 14. HC was 19 ppm.

[0111] <Polyol component> PTMEG1000: Polytetramethylene ether glycol, number average molecular weight (Mn) 1000 PTMEG650: Polytetramethylene ether glycol, number average molecular weight (Mn) 650 PBA1000: Condensation polyester diol (polybutylene adipate), number average molecular weight (Mn) 1000 PCL1000: Polycaprolactone diol, number average molecular weight (Mn) 1000 PC1000: Polycarbonate diol, number average molecular weight (Mn) 1000

[0112] <Chain extender> 1,4-BD: 1,4-butanediol

[0113] <Urethanization catalyst> DBTDL: Dibutyltin dilaurate, an organotin catalyst

[0114] 2. Prepolymer composition and polyurethane resin Examples 1 to 17 and Comparative Examples 1 to 3 (1) First step The polyisocyanate component and the polyol component were reacted under a nitrogen atmosphere according to the formulation and conditions shown in Tables 1 to 3. The polyisocyanate component and the polyol component were mixed so that unreacted polyisocyanate component (isocyanate monomer) remained. In Tables 1 to 3, the equivalent ratio R in the first step indicates the equivalent ratio R (NCO / OH) of the isocyanate group in the polyisocyanate component to the hydroxyl group in the polyol component.

[0115] (2)Second process Next, the reaction product solution was subjected to thin-film distillation under the formulation and conditions shown in Tables 1 to 3 until the isocyanate monomer content reached 0.1% by mass, yielding a purified solution of isocyanate-terminated prepolymer. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the isocyanate-terminated prepolymer were measured using the purified solution under the conditions described below. The polydispersity (Mw / Mn) of the isocyanate-terminated prepolymer was also calculated.

[0116] (3) Third step An isocyanate monomer and a urethane catalyst as an additive were added to the purified liquid of the isocyanate group-terminated prepolymer according to the formulations shown in Tables 1 to 3. This gave a prepolymer composition.

[0117] In Tables 1 to 3, the amount of added monomer indicates the ratio of the isocyanate monomer to the total amount of the purified liquid of the isocyanate-terminated prepolymer and the isocyanate monomer. Note that in Comparative Example 1, Example 9, Example 11, Example 12, Example 14, and Example 16, no isocyanate monomer was added.

[0118] (4) 4th step A prepolymer composition and a chain extension component were prepared according to the formulations shown in Tables 1 to 3 and heated to 60°C. In the presence of a urethanization catalyst shown in Tables 1 to 3, the prepolymer composition and the chain extension component were mixed for 60 seconds and then degassed under reduced pressure at room temperature for 60 seconds. The mixture was then poured into a mold at 110°C and reacted at 110°C for 16 hours, followed by aging at 23°C for 3 weeks. This yielded a polyurethane resin (cast polyurethane elastomer). The amount of urethanization catalyst (ppm) in the tables indicates the ratio of the urethanization catalyst to the total amount of the prepolymer composition, chain extension component, and urethanization catalyst.

[0119] 3. Physical property measurements (1) Dispersity (Mw / Mn) The prepolymer composition was subjected to GPC measurement using a gel permeation chromatograph equipped with a differential refractometer. Polystyrene was used as the standard substance. Based on the results of the GPC measurement, the weight average molecular weight (polystyrene equivalent, Mw), number average molecular weight (polystyrene equivalent, Mn), and dispersity (Mw / Mn) of the isocyanate group-terminated prepolymer were calculated. The specific GPC measurement method is described below.

[0120] Specifically, 0.05 g of isocyanate-terminated prepolymer (purified liquid) was dissolved in 1 to 2 mL of methanol in a glass bottle and left at room temperature for about three days. This resulted in the sample being converted into methyl urethane. If the sample was not soluble in methanol, dichloromethane (cosolvent) was added to dissolve the sample.

[0121] The sample was then heated to 50°C while blowing N2 onto it to volatilize the solvent containing methanol. This resulted in a solid sample. The sample was dissolved in N,N'-dimethylformamide (DMF) to obtain a 0.625% by mass solution. The resulting solution was subjected to GPC measurement under the following conditions.

[0122] (1) Analytical equipment: HLC-8220GPC (Tosoh Corporation) (2) Pump: Attached to the device (3) Detector: Attached to the device: RI detector (4) Eluent: DMF (LiBr 0.86g / L) (5) Separation column: SuperAWM-H x 3 Manufacturer: Tosoh Corporation Product code: 19320 (6) Measurement temperature: 40℃ (7) Flow rate: Sample pump 0.6 mL / min, reference pump 0.6 mL / min (8) Sample injection volume: 20 μL (9) Analysis equipment: Analysis software GPC-8020mII (Tosoh Corporation) System correction (10) Standard material name: Polystyrene

[0123] (2) Isocyanate group concentration The isocyanate group concentration was measured in accordance with the n-dibutylamine method of JIS K 1556 (2006).

[0124] 4. Evaluation (1)Hardness The Shore D hardness of the polyurethane resin was measured in accordance with JIS K 7312 (1996).

[0125] (2) Low heat generation The loss factor (tan δ) of the polyurethane resin was calculated as an index of low heat buildup. More specifically, the dynamic viscoelasticity spectrum of the polyurethane resin was measured using a dynamic viscoelasticity measuring device (IT Measurement & Control Co., Ltd., Model: DVA-220) under the following conditions: measurement start temperature -100°C, heating rate 5°C / min, tensile mode, gauge length 20 mm, static / dynamic stress ratio 1.8, and measurement frequency 10 Hz. The loss factor (tan δ) at 40°C was then calculated.

[0126] [Table 1]

[0127] [Table 2]

[0128] [Table 3]

[0129] The above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and should not be interpreted as being limiting. Modifications of the present invention that are obvious to those skilled in the art are intended to be included in the scope of the following claims. [Industrial Applicability]

[0130] The prepolymer composition, polyurethane resin, elastic molded article, and method for producing the prepolymer composition of the present invention can be used in a wide range of applications, including, for example, transparent hard plastics, waterproof materials, potting agents, inks, binders, films, sheets, bands, belts, shoe press belts, tubes, blades, speakers, sensors, outsoles, threads, fibers, nonwoven fabrics, cosmetics, shoe accessories, heat insulating materials, sealing materials, tape materials, sealing materials, solar power generation components, robot components, android components, wearable components, clothing components, sanitary products, cosmetics, furniture components, food packaging components, and so on. Suitable for use in sports goods, leisure goods, medical supplies, nursing care products, housing components, acoustic components, lighting components, vibration-damping components, soundproofing components, daily necessities, miscellaneous goods, cushions, bedding, stress absorbing materials, stress relaxation materials, automotive interior materials, automotive exterior materials, railway components, aircraft components, optical components, office equipment components, miscellaneous surface protection materials, semiconductor encapsulants, self-repairing materials, health appliances, eyeglass lenses, toys, packing, cable sheaths, wire harnesses, telecommunications cables, automotive wiring, computer wiring, industrial goods, shock absorbing materials, semiconductor products, and bridge bearings.

Claims

1. A prepolymer composition containing an isocyanate group-terminated prepolymer, the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component containing a macropolyol; The number average molecular weight of the macropolyol is 650 or more and 2000 or less, the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer is 1.85 or less, The prepolymer composition has an isocyanate group concentration of 14.0 mass% or less.

2. The present invention relates to a method for producing a polymer composition comprising: the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component containing a macropolyol; The number average molecular weight of the macropolyol is 650 or more and 2000 or less, the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer is 1.85 or less, The polyurethane resin, wherein the prepolymer composition has an isocyanate group concentration of 14.0 mass% or less.

3. An elastic molded article comprising the polyurethane resin of claim 2.

4. A method for producing a prepolymer composition containing an isocyanate group-terminated prepolymer, comprising: A first step of reacting a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane with a polyol component containing a macropolyol to prepare a reaction product liquid containing an isocyanate group-terminated prepolymer; a second step of distilling the reaction product liquid; Equipped with In the first step, the equivalent ratio (NCO / OH) of the isocyanate group in the polyisocyanate component to the hydroxyl group in the polyol component is 7.0 or more, The number average molecular weight of the macropolyol is 650 or more and 2000 or less, the polydispersity (Mw / Mn) of the isocyanate group-terminated prepolymer is 1.85 or less, The isocyanate group concentration of the prepolymer composition is 14.0% by mass or less. Method for producing a prepolymer composition.

5. a third step of adding an isocyanate monomer to the purified liquid obtained by the distillation after the second step; The method for producing a prepolymer composition according to claim 4, wherein the isocyanate monomer comprises 1,4-bis(isocyanatomethyl)cyclohexane.

Images